Extra inning: Power, perseverance of Astros’ Chris Carter

First, Chris Carter was bad. Then he was good. Then he was streaky. Then he was bad again.

Finally, Carter’s learning to hit.

Working since spring training with hitting coach John Mallee, the eight-year minor leaguer and first-year everyday player has clearly been the Astros’ best power hitter this season. Now, he has a chance to become the organization’s first 30-homer man since Lance Berkman (34) and Carlos Lee (32) reached the mark in 2007.

Carter went 2-for-3 with two home runs and a career-high four RBIs Wednesday during the Astros’ 4-1 victory against the Tampa Bay Rays at Minute Maid Park. He drove in all of the Astros’ runs and recorded his second two-homer game this season (April 9 at Seattle).

Carter’s the first Astro since Berkman to reach 17 homers by July 3 and is just one blast away from Justin Maxwell’s team-high 18 in 2012. The 6-foot-4, 245-pound slugger has reached base safely in 15 of his last 16 games, hitting .315 with four homers and 10 RBIs during the stretch.

Carter’s turnaround began quietly in mid-June, when he began receiving private praise from Astros coaches, despite the fact his batting average bottomed out at .210. While his strikeouts also continued to pile up — an MLB-leading 115 as of Wednesday — Carter’s plate discipline and at-bat awareness were gradually improving via video work, cage sessions and pregame instruction from hitting coach John Mallee, among others.

During May, even Carter’s biggest supporters within the Astros wondered if his swing was fixable. Now, the 26-year-old’s on the verge of becoming the team’s in-season most-improved-player. He’s done it all while trusting in Mallee and not listening to those who implored him to be more aggressive early in counts.

Carter saw 15 pitches from two Rays pitchers during his home-run at-bats Wednesday. After the game, Porter attached 30-home run and 100-RBI potential to a player Oakland willingly dealt away during February in the Jed Lowrie trade.

Porter on Carter: He obviously was pretty good tonight. I keep saying it and saying it: When this guy stays on the ball and gets pitches in the strike zone, he is (an) extremely dangerous man. Tonight was no exception. He fouled off some tough pitches, laid off some tough pitches and really was patient enough to get the ones that he can drive and he didn’t miss ‘em tonight. Those two balls were squared up pretty good.

Porter on Carter working with Mallee: John Mallee has done a tremendous job and I told him that a few days ago, just watching the quality of Chris’ at-bats. You look at the strikeout total — yes, it’s there. But you look at the power numbers, the RBIs and you just look over the last two and a half, three weeks — just the quality of the at-bats overall — I mean, he has a chance to hit 30 home runs and drive in a 100. And when you see that kind of progression and you see that kind of adjustments being made, you really say to yourself, ‘Moving forward, this guy has a chance to be a middle-of-the-order bat that could be very productive.”